Torch control apparatus



Jan. l2, 1937. D. L. SMITH TORCH common APPARATUS Filed July 31, 1935 2 Sheets-Sheet; l

INVENTOi ATTORNEY D. L. SMITH TORCH CONTROL APPARATUS Jan. 12, 1937.

Filed July 51, 1935 2 Sheets-Sheet 2 9 IIEEE re 9 o 7 32 w 5 .W 9 E/ II o m 4 IINVENTOR W M I A'n'oNEY Patented Jan. 12, 1937 UNITED ASTJ'IIATES TORCH CONTROL APPARATUS Donald L. Smith, Caldwell, N. J., asslgnor to Air Reduction Company, Incorporated, New York, N. Y., a corporation of New York Application July 31, 1935, Serial No. 33,959 1 l 1:; Claims; (01. 205-9) This invention "relates to apparatus for controlling the gas supply to the torches of skelpheating retorts used in the manufactureof welded I or tubing by passing the edges of flat or partially formed skelp through retorts in which torches direct high-temperature flames against the skelp 1o edges, and then forming and welding the tube by means of a die or rollers located beyond the retort. The oxy-fuel gas flames of the torches in the retorts are hot enough to melt the skelp edges away :quickly, if these edges did not" move 15 through the retort with continuous motion and at high speed. The amount of heat put into the edges can be controlled to raise the edges to a suitable temperature for making a pressure weld, or to actually produce sufflcient melting of the 20 edge faces to make a fusion weld when the faces are brought together in the closing die or rollers.

vantages in both economy and operation, however, in preheating the skelp in a furnace. 4 Various means for moving the skelp through 30 the retort can be employed, but the skelp is usually'pulled through the retort-by a draw-bench, and the forming and welding done in a bell die held in the head-block of the draw-bench.

It is an object of this invention to control the operation of the retort torches more advantageousl' than heretofore, and another object is to co bine improved control vmeans with retort and draw-bench apparatus for making welded pipe or tubing.

43 Another object of the invention is to shut ofl .all gas from both retort torches in the event of a flash-back in either of the torches, the term flash-back being usedin this specification in abroad sense to include situations in'which the flame flashes into the burner or torch tip and then ceases to burn, leaving the torch extinguished, or continues to burn within the torch, but without traveling back through a gas conduit, and to include back-fires in which the flame does travel back through a gas delivery conduit.

55 torches are close together and the heat from a 'It is particularly advantageous to cut oil? the burning torch will damage an opposing extinguished torch during the time when there is no skelp between the torches.

Other objects, features and advantages of the invention will appear or be pointed out as the specification proceeds.

In the accompanying drawings, forming part hereof: a

Fig. 1 is a diagrammatic plan view showing a draw-bench and one end of a skelp-heating fur- 1o nace with a retort between the furnace and drawbench, and with-means forcontrolling the gas supply to the retort in accordance with this in-' vention;

Fig. 2 is an enlarged view, partly 'in section, on the line 22 of Fig. 1;

Fig. 3 is an enlarged sectional view of a pressure operated switch of the torch control means, the section beingtaken on the line 3-3 of Fig. 4;

Figs. 4 ahd 5 are sectional views on the lines 4-4 and 5-5 of Figs. 3 and 4, respectively; and

Fig. 6 is an enlarged sectional view of one of the solenoid-operated valves of the torch control .means of Fig. 1.

Strips of skelp l I are successively placed 'in a furnace l2. An attendant, commonly referred to as the welder, stands near the exit of the furnace, and as each skelp becomes heated to a degree somewhat below the welding state and below the temperature at which the strength of the metal becomes seriously impaired the welder reaches into the furnace with a tongs l4, grips the end of the skelp, and hooks the handle of the tongs to the chain l5 of a draw-bench It. The skelp is drawn through a retort [8, which heats the edge faces of the skelp, and through a bell die l9 which bends the skelp into a tube and brings the edges together to make a weld.

The draw-bench is supported on a pivot 20 at one end and on rollers 22 at the other end. The I rollers 22 move along a track 23 and permit angular movement of the draw-bench to align it with the strip of skelp which is to be pulled from the furnace. The chain l5 runs over sprockets at both ends of the bench. The sprocket at the end 4:; remote from the furnace is driven by a motor 25 through reduction gearing 26. The attendant who operates the draw-bench occupies a'position near the motor-end of the draw-bench where he can watch the movement of the skelp from the timeit leaves the furnace until the entire length of the skelp has been drawn through the bell.

The retort I8 is supported on a platform 2| connected to or forming a part of the end casting of the draw-bench. The retort includes guides 56 through which the edges of the skelp travel in close proximity to heating burners or torches. 3| and 32. These torches are preferably oxyacetylene torches, and each one directs an elongated system of flame against one of the edge faces of the skelp. The burners from which the gases issue may be made an integral part of the retort if desired.

The oxygen and fuel gas supply to the torches can be turned on and oil by means of electric switches located on a support 34 extending from the draw-bench within convenient reach of the welder when he is standing at his station near the'exit end of the furnace. The welder does not see what happens to the skelp after it passes beyond the retort, and may not be immediately aware of the accident if the tongs pull oif the end of the pipe, or the metal breaks as a result of being overheated in the furnace. Such accidents cause the skelp in the retort to stop, and unless the torches are quickly extinguished the skelp in the retort melts along its edges and part of it flows into the air passages and lower parts of the retort, necessitating considerable loss of time in opening and cleaning the retort. The draw-bench operator can watch the pipe during the entire welding operation, and by means of an emergency switch can cut oi the gas supply to the torches immediately in case of accident.

Acetylene or other fuel gas is supplied to the torches 3| and 32 through conduits 36. Each of these conduits communicates with a safety device 31 which includes an electric switch and means for operating the switch, in the event of a sudden rise in the gas pressure, to effect a shutting oif of the gas supply to the torch. A flashback'always causes at least a momentary pressure rise in the conduit. The construction of the safety device 31 will be described in the explanation of Figs. 3-5.

torches through conduits 4| and valves .42 operated by solenoids 43 similar to those associated with the acetylene lines.

Each of the solenoids 40 is connected with a single-pole, double-throw switch 45 and with a return power line 46. When either of the switches 45 is closed against its lower contact it connects its associated solenoid 40 with a power line 41. Each of the solenoids 43 is simflarly connected on one side with the return power line 46 and on the other side with 'a single-pole, double-throw switch 49 which can be closed against its lower contact to connect the solenoid with the power line 41.

When the switches 45 are closed against their upper contactsthey close circuits between the solenoids 40 and a contact 5| of a relay 52. The power line 41 connects with a contact 53 of the relay 52, and when this relay is energized a contact bar 54 closes the circuit between the contacts 5| and 53 so that power is supplied to the solenoids 40.

The upper contacts of the switches 49 connect with contacts 56 and 58 of a relay.51. When this relay 51 is energized it causes a contact bar 59 to close a circuit between the contact 56 and a contact 6.0 which connects with a switch contact 6| and with the contact 51 of relay 52.

The magnets of the relays 52 and 51 are connected with the line 46 through a normally-closed switch 62 on the support 34 of the draw-bench and a normally-closed emergency switch 63 located within convenient reach of the drawbench operator.

The other side of the magnet of relay 52 is connected with a relay contact 65 and with a l conductor 66. This conductor 66 connects with contacts 10 and 1| of a starting control 12 located on the support 34 of the draw-bench within convenient reach of the welder.

The starting control 12 includes two normally open, single-throw switches 14 and 15 which can be closed successively by a plate 16. This plate covers the switches 14 and 15 and'is pivotally supported at its center so that it can be rocked to the right or left to close either of the switches 14 and 15.

-When the switch 14 is closed, it completes a circuit from the power line 41, through the contact 1D, and conductor 66 to the relay 52 and causes the relay to be. energized so that it draws a contact bar 18 against the contact 65 and a contact 19. A conductor connects the contact 19 with one side of the switch in the safety device 31 which is operated by gas flowing to the torch 3|. The other side of the switch in this safety device 31 is connected by a conductor 82 with one side of the switch in the safety device 31 which is associated with the conduit 36 supplying fuel gas to thetorch 32. The other sidev in either of them breaks the circuit from the power line 41 through contacts 53 and 5|, conductors 83 and 82 to the contact 13. It is this circuit through the safety devices 31 which keeps the magnet of relay 52 energized after this relay has been initially closed by operating switch 14.

The magnet of relay '51 is connected with a contact 85 of the relay and with the switch 15. When the switch 15 is closed,-the magnet of relay 51 receives power from the contact 5| of relay 52, if that relay is closed so that contact 5| is connected with the power line 41. If the relay 52 is open at the time the switch 15 is closed, then the closing of this switch has no effect. This circuit construction makes it necessary to'close the switch 14 and energize the relay 52 which causes the acetylene valves to open, before the switch 15 can be operated effectively to energize the relay 51 and cause the oxygen valves to open.

The rocking plate 12 makes it impossible to close both of the switches "and 15 simultaneously. Each of these switches is normally open, and when closed by the plate 12 springs open as soon as the welder permits theplate to 'move back into its level position. When the relay 51 is energized, it draws a contact bar 81 against the contacts 58 and 85 and closes a circuit parallel to the switch 15 to maintain the circuit of the relay complete after the switch 15 opens. I This circuit may be traced from the power line 41 through contact Closing of the switch 15 also completes a circuit.

parallel to that through the safety devices 31 for keepingthe relay 52 energized when the switch 15is closed. Sucha circuit prevents the.

relay 52 fromopening in the event that the first rush of oxygen gas, which accompanies the op- 75 eration of .the switch IL causes a switch in the safety devices 31 to open.

Although the pressure rise caused in the aoetylene lines by opening of the oxygen valves is not 5 large, this parallel circuit closed by the switch I5 makes practical the use of more sensitive safety devices 31. The circuit exte ds from the power line 41 through contact 53, ar 34, contact 5|,

switch I5, and conductor 83 to the magnet of relay 52.

Figs. 3-5 illustrate the construction of one of the safety devices 31, the other being of, similar construction. A safetydevice 31 includesaconduit pressure chamber 9| and a counterbalancingv diaphragms 94 and 35 have their center portions 1 clamped to a connector 86 so that any movement of either diaphragm is transmitted to the other. The chambers 9| and 92 communicate through 25 a conduit 98, which has a restricted portion I for causing a time lag between a pressure change in the chamber 9| and a'corresponding pressure change in the counterbalancing pressure chamber. The length of this time lag depends on the 1 size of the restricted portion I00 of the conduit 33 and on the capacity of the counterbalancing pressure chamber 92. An abutment |0| limits the upward movement of the diaphragm in case of a very sudden excessive pressure rise in the 35 conduit chamber 3|. Y I

An electric switch I02 is supported between the diaphragms 94 and 95 by an arm I04, which is best shown in Figs. 4 and 5. The arm I04 is sup- 1 ported at one end by a shaftl05, which extends 40 through the end of this arm and through the casing of the safety device 31. The arm I04 has a limited pivot movement about .the axis of the shaft I05. The other end ofthe arm I04 extends between opposing limit screws I06 and I01, which 45 thread through portions of the safety device 31 and are held in position by lock nuts I08.

The free end of the arm I04 rests on the lower limit screw I06, and a leaf-spring 0, which is fastened to the arm, is confined between the arm 50 and the upper limit screw I01. The arm I04 does not move during the ordinary operation of the safety device, but the spring will yield and per-.

mit the switch and diaphragm to rise if the up- \ward pressure of the diaphragm 35 becomes so 55' great that it is likely to damage the switch. The

screw I00 is adjusted to bring the switch I02 into proper relation with the diaphragm 95 and connector 98. Thescrew I0! is adjusted to obtain suflicienttension in the spring IIO to insure operso ation of the switch 92 before the spring yields.

- The switch I02 is shown in Fig. 4 as a simple form of spring-operateglswiteh with a fixed contact 2 connected to e switch housing, which is of insulating material. A movable contact I I3 65 is carried at one end of a leaf spring I and the other end of this leafspring is secured to the switch housing. Thetension of the spring 'I I4 normally holds the contact 3 against the contact II 2. A push rod 5 extends through the 70 switch housing and contactswith' the spring 4 close to its fixed end so that a small movement of the push rod 5 causes a much larger movement at the contact end of the spring and moves the contacts apart to open the circuit. In order that 75 the switch may be longer wearing, a snap-action stem I23 is made of non-magnetic material.

3 switch may be employed. The current which passes through the switch is small, however, since it is a relay operating current and not that supplied to the valve-operating solenoids.

The valves 39 and 42 are of similar contruc- 5 tion and so are their solenoid operating means. Fig. 6 shows the construction of one valve 33 and its solenoid 40.

The valve 39' contains a valve element 8 which is urged into closed position by a spring 10 I IS. The valve closes in the direction of the gas ,flow and the upstream pressure of the gas is eflective'to hold the valve closed.

The solenoid 40 operates a plunger I2|. When the solenoid is not energized, the plunger |2| is held in an elevated position by a spring I22. A stem I23 extends downward from the plunger |2I to within a short distance of the stem of the valve element H8. When thesolenoid 40 is encrgized, it draws the plunger I,2I downward against the force of the spring I22 and causes the stem I23 to move into contact with the stem of the,

valve element 8 and displace the stem 30 that the valve is moved into open position. I

The force required to open the valve is greater 25 than the force required tohold it open because the gas pressure below the valve element 8 resists opening of the valve, but this pressure is largely counterbalanced by the gas pressure of the other side of the valve element after it is moved into open position and gas is flowing around it. The initial gap between the stem of the valve element 8 and the lower end of the stem I23 permits the plunger -|2I to start moving and gain considerable momentum before it encounters the resistance oiiered by the valve element. The plunger stem I23 strikes a-hammer blow against-the stem of the valve element 8 to impart the initial movement to the valve element. This featm'e of the valve operating means 49 makes possible the use of a smaller solenoid than would be required if there were no lost-motion between the plunger and valve element. The force exerted by the solenoid is greater if the 45 The operation of the invention is as' follows: The plate I8 is first rocked to the right in Fig. 1 to close the switch 14 and energize the relay 52. Closing of the relay 32 supplies power to both of the solenoids 40 if the switches are closed against their upper contacts. These .switches 45 are always closed against their lip-.-

per contacts except when the solenoids are to be. operated independently of the control circuits.

When' power is supplied to the solenoids 40, they operate to open the valves 33 so that acetylene can flow through the conduits 36 to the torches 3| and 32.

If the first rush of acetylene gas causes a/sudden pressure change in the safety devices 31 sufflcient to open the switches in these safety devices, the power to the solenoids 40' is not interrupted because the welder has the switch I4 closed at the time the first rush of gas reachesthe safety devices, and the circuit completed by the switch I4 cannot be broken by the safety devices.

The torches are lighted, and the plate I0 is then rocked to the left to close the switch II and energize-the relay 51. The relay BI closes and supplies power to the solenoids 43, causing them to open the valves 42 so that oxygen flows through the conduits 4| to the t rches 3| and 32. o

The skelps II are drawn successively from the furnace |2' and pulled through the retort I3 and bell I9by means of the draw-bench I0. In case of any accident which causes the skelp to stop in the retort, or if for any other reason it becomes desirable to extinguish the torches in the retort, the welder can do so by opening the push-button switch 62, or the draw-bench operator, who is in a better position to seeany accident, can extinguish the torches by opening the emergency switch 63.

Either of the acetylene valves 39 can be opened at any time regardless of the control means by closing the switch 45 of the associated solenoid against its lower contact. The'swltches 49 may be similarly operated to open the oxygen valves 42. This, operation of the valves independently of the control mechanism is advantageous for test purposes. r s

Changes and modifications may be made in the apparatus illustrated and some features of the invention can be used alone without departing from the invention as defined in the claims.

I claim:

1. The combination of a retort having torches, one for heating each of the edge faces of skelp as'it moves through the retort with continuous motion, conduitsfor supplying gas to both torches including separate conduits for oxygen and fuel gas, valve means in said conduits, and automatic control means responsive to a flash-back in either torch for causing the-valve means to shut off the supply of gas through at least one of the conduits to both torches.

2. skelp-heating apparatus comprising a retort, separate burners in the retort in position to direct flame jets against each of the edge faces of skelp as it travels through the retort, conduits for supplying oxygen to the burners, other conduits for supplying fuel gas to the burners, valve means for closing said conduits, and control means operated by a fiash-back in either burner for closing the'valve' means and shutting off both the oxygen and fuel gas supply to both burners.

3. The combination of a retort having means for directing gasjets against the edges of skelp to heat said edges in the manufacture of welded pipe or tubing, andconduits for supplying gas to the burners, of valve means for shutting off the supply of gas, and means for causing said valve means to close, including a safety device operated by a sudden change of pressure in one of said conduits.

4. Apparatus for heating the edges of skelp in the manufacture of welded pipe and tubing, said apparatus including a retort through which the edges of the skelp travel with continuous motion, means in the retortfor directing gas jets against both edges of the skelp to heat saidedges, conduits for supplying gas tothe heating means in said retort, valve means for shutting oil all gas from said conduits, and a safety device for controlling the closing of the valve means, said safety device including a diaphragm exposed to the gas pressure in the conduit, a balancing pressure chamber, a restricted conduit through which'the balancing pressure chamber communicates with the conduit, andmeans operated by displacement ,of the diaphragm when the pressure in the conduit is substantially different from the pressure in the chamber for causing the valve means to close.

5. The combination with a retort having two torches, one in position to heat each edge face of a skelp as it is drawn through the retort, of manual control means operable to supply gasto both torches at the same time, and automatic control means responsive to a flash-back in either torch for shutting off gas from both of said I torches.

6. The combination with a retort having .two torches, one in position to heat each edge face of a skelp as it is drawn through the retort, of conduits for supplyingv oxygen to the torches, other conduits for supplying fuel gas to the torches, separate valve means for the oxygen and fuel gas conduits, manually operated control apparatus for the valve means including elements requiring operation of the valve means to supply fuel gas to the torches before said valve means the skelp, mechanism for causing the skelp to move through the retort and through closing apparatus which brings the skelp edges together to make a welded tube, automatic control means for shutting oi? the supply of gas to the torches in case of a flash-back, and auxiliary control means for the gas supply including an emergency shutoff device in position to be actuated by the person operating the mechanism that causes the skelp to move through the retort and closing apparatus.

8. The combination with, tube making apparatus including a skelp heating furnace, a bell 'die for forming the skelp into a tube and bringing the skelp edges together to make aweld, a retort between the furnace and hell with torches for heating the edges of the skelp as it passes from the furnace to the bell, and a draw-bench for pulling the skelp from the furnace and through the retort and bell, of automatic control means for cutting off the supply of gas to the torches in case of a flash-back, and emergency manual control means for the gas supply in position to be actuated'by the draw-bench operator. 9. Apparatus for the manufacture of welded pipe and tubing including a draw-bench, a skelpheating furnace, a bell die at the furnace end, of the draw-bench, a retort between the furnace] 7 being located close to the retort in position to be" actuated by the attendant who pulls the skelp from the furnace and connects it with the drawbench, safety devices for automatically cutting off the supply of gas to the torches in the event of a flash-back, and emergency manual control, means for shutting ofl gas from the torches, said emergency manual. control means being located in position to-be actuated by the draw-bench operator at the end of the draw-bench remote from the furnace.

10. In apparatus for making welded pipe or tubing, the combination with two torches located in positions to heat the opposite edge faces of the metal before the edges are-brought together to make a weld,"of separate valves for controlling the supply of gas to the respective'torches, and means responsive to a flash-back in either torch for closing the valverand shutting off the supply of gas to both torches.

11. In apparatus for making welded pipe or tubing, the combination with two torches located in positions to heat the opposite edge faces of the metal before the edges are brought together to make a weld, of separate valves for controlling the supply of gas to the respective torches, electromagnetic means for operating eachof said valves, and a common switch for supplying power to both: of the electromagnetic means to.cause the valves to operate simultaneously.

12. Welding apparatus including two torches, separate conduits for supplying gas to said torches, valve means for shutting off the gas from said conduits, and control mechanism for operating the valve means to start or shutoff the gas supply to both torches simultaneously.

13. Welding apparatus including two torches, separate conduits for supplying fuel gas to said torches, separate conduits for supplying oxygen to said torches, a valve in each fuel gas conduit,.

, a valve in each oxygen conduit, and common control means for operating both fuel gas valves simultaneously and for operating both vof the oxygen valves simultaneously.

14. Welding apparatus including two torches, separate conduits for supplying fuel gas to said torches, separate conduits for supplying oxygen to said torches, a valve in each fuel gas conduit, a valve in each oxygen conduit, and common control means for operating both fuel gas- 7 each torch.

15. Welding apparatus including two torches, separate conduits for supplying fuel gas to said torches, separate conduits for supplying oxygen to said torches, a valve in each fuel gas conduit,

a valve inv each oxygen conduit, and common control means for operating both fuel gas valves simultaneously and for operating both of the oxygen valves simultaneously, said common control means including apparatus preventing opening of the valves in the oxygen'conduits ahead of the off the supply of oxygen from each torch, com

mon manual control means-for operating both of the fuel gas valves simultaneously and for operating both of.the oxygen valves simultaneously, and automatic control means, responsive 1'7. Apparatus for controlling the supply of gas to two oxy-fuel gas welding torches including separate valves for shutting off the fuel gas supply from each torch, separate valves for shutting ofi the supply of oxygen from each torch, common manual control ,means for operating both of the fuel gas valves simultaneously. and for operating both of the oxygen valves simultaneously, said control means including apparatus requiring opening of the fuel gas valves before the oxygen valves can be opened, and safety devices connected with the valve control means and constructed and arranged to cause the valves to close in the event of a flash-back in either torch PONALD L. SMITH.

.to a flash-back in either torch, for closing all of .said valves. 

